@thomasfuchs avoid hobbyist refurbs.
Inside that battery are eight industrial 18650 cells welded together under factory conditions.
Hobbyists can only buy those loose and without protection circuits. So if they miscalculate the voltage or botch their welds/solders, their replacement is a death trap.
Imagine someone firing a shotgun shell into your lap at point blank range, and then dousing your legs in toxic chemicals that are also on fire & can't be put out without a powder extinguisher.